Uterine fibroids are common growths that develop within or on the uterus. These growths are typically non-cancerous. This article explains what uterine fibroids are and clarifies their relationship with cancerous conditions.
Understanding Uterine Fibroids
Uterine fibroids, also known as leiomyomas, are benign tumors composed of muscle and connective tissue that form in or on the wall of the uterus. They are common, affecting an estimated 20% to 80% of women by age 50. Many individuals with fibroids experience no symptoms, and their presence may only be discovered during a routine pelvic examination or imaging.
Fibroids can vary widely in size, ranging from microscopic to large masses that can alter the shape of the uterus. Their location also varies, with types including intramural (within the uterine wall), subserosal (on the outer surface), and submucosal (under the inner lining of the uterus). When symptoms occur, they often include heavy or prolonged menstrual bleeding, pelvic pressure or fullness, frequent urination due to bladder pressure, and pain during sexual intercourse.
The Link Between Fibroids and Cancer
Uterine fibroids themselves are almost always benign and do not become cancerous. Having fibroids does not increase an individual’s risk of developing other forms of uterine cancer.
However, a very rare form of uterine cancer called leiomyosarcoma (LMS) can sometimes be mistaken for a fibroid because both are smooth muscle tumors found in the uterus. Unlike benign fibroids, leiomyosarcoma is an aggressive cancer that typically arises de novo, meaning it originates as a new cancerous growth rather than from an existing fibroid. The incidence of leiomyosarcoma is extremely low, occurring in less than 1 in 1,000 cases of uterine masses initially thought to be fibroids, or approximately 1 in 100,000 people per year.
Differentiating Benign Fibroids from Malignant Growths
Distinguishing between benign fibroids and the rare malignant leiomyosarcoma is important for medical evaluation. Healthcare providers use various diagnostic approaches to assess uterine masses.
Imaging techniques, such as ultrasound and magnetic resonance imaging (MRI), are commonly employed to visualize the uterus and any growths. MRI is particularly useful in differentiating these conditions due to its ability to provide detailed images and assess tissue characteristics, including signal intensity and the presence of features like hemorrhage, which can be more indicative of malignancy.
While imaging can raise suspicion, a definitive diagnosis of leiomyosarcoma typically requires a tissue biopsy, often obtained after surgical removal of the mass. Indicators that might prompt a healthcare provider to suspect a malignant growth include rapid enlargement of a uterine mass, especially in postmenopausal women, or new and unusual symptoms.
When to Consult a Healthcare Provider
Consult a healthcare provider if you experience symptoms that could indicate uterine fibroids or other gynecological conditions. Symptoms warranting medical attention include new or significantly heavier or prolonged menstrual bleeding, bleeding between periods, or worsening pelvic pain.
A feeling of pressure or fullness in the lower abdomen, frequent urination, or changes in bowel habits like constipation also suggest a medical evaluation is appropriate. Rapid enlargement of the abdomen or any new or changing symptoms, particularly in postmenopausal women, should also prompt a visit to a healthcare provider.
Early consultation allows for proper diagnosis and management.